Bone age assessment is a procedure frequently performed on pediatric patients to evaluate their growth. It is an important procedure in the diagnosis and management of endocrine disorders, diagnostic evaluation of metabolic and growth abnormalities, deceleration of maturation in a variety of syndromes, malformations, and bone dysplasias. It is also used for consultation in planning orthopedic procedures. The most common clinical method for bone age assessment is atlas matching by a left-hand wrist radiograph against a small reference set of atlas patterns of normal standards developed by Greulich and Pyle in the 1950s based on data collected in the first half of the 20th century. (The Tanner-Whitehouse method is a second method that requires extensive measurement and comparison of 20 bones against 9 possible stages of development. It is tedious and unsuitable for a clinical environment and thus, rarely used.) Unfortunately, the Greulich and Pyle reference radiographs do not reflect skeletal development in children and adolescents of today's European, African, Hispanic or Asian descent. Increasing racial diversity in the United States, as well as changing nutritional and behavioral habits of children, show a need for reevaluation of the use of skeletal age standards. Our preceding efforts have validated and confirmed the need for continued study. This application is the third phase of our continuing effort and intends to complete the development of a flexible, more relevant digital hand atlas system that exploits novel trends in both demography and technology. The digital atlas will be a large standard set of normal hand and wrist images of children of four diverse ethnic groups. It is comprised of 1,080 (already collected and read) + 400 (to be collected) reference images and computer-extracted bone objects and quantitative features, removes the disadvantages of the out-of-date, ethnically constrained Greulich-Pyle atlas and the tediousness of Tanner and Whitehouse scoring method. These images are collected from evenly distributed normal 1 to 18 years of age, male and female, European, African, Hispanic, and Asian descent. A Web-based computer-aided diagnostic system for bone age assessment will be implemented where quantitative features similar to those in the atlas are extracted on a Web sewer and then compared with patterns from the digital atlas database as well as computer generated scores to assess the bone age. By the end of this study, we will have completed a digital hand atlas fully integrated with a Web-based sewer for quantitative, consistent, and reliable bone age assessment that can be performed anywhere, anytime. The user interface will be simple to apply and resemble current bone age assessment procedures. Two immediate benefits will be realized: improved real-time clinical bone age assessment and the production of a research tool that will allow for ongoing evaluation of the traditional gold standard techniques for bone age assessment. These advantages combined with higher accuracy and fast turn around time in diagnosis would gain acceptance by both pediatric radiologists and other clinicians.